# #A/B=B/A" "# is true if?

##### 2 Answers

Jun 24, 2018

# A= +- B #

#### Explanation:

If

#A/B * AB = B/A * AB#

# :. A^2 = B^2#

# :. A^2 - B^2 = 0#

# :. (A-B)(A+B)= 0#

# { (A-B= 0=> A=B), (A+B= 0=> A=-B) :} #

Thus there are two possibilities

# A= +- B #

Cross multiply

#### Explanation:

as above